1. Field of the Invention
This invention relates to a cassette and associated spool for film, sound track and like material, with means for the mutual support of the outer areas of the spool flanges.
2. Description of the Prior Art
If a spool of this type is placed in the casette in an empty or only partially filled condition, the area of the uppermost flange of the spool projecting beyond the core of the spool is not supported, so that it sags out of its normal position to a greater or lesser degree, depending on the thickness of the flange. This phenomenon becomes particularly noticeable after considerable use of the spools, if the material used, today almost exclusively plastics, exhibits signs of fatigue. This sagging of the upper spool flange leads in time to permanent warping of the spool so that even when fully supported the flange no longer assumes its original shape. The result of this is that the film running off drags on the outer areas of the inner sides of the flanges and is thus subject to damage. In any event, free running-off of the film with spools distorted in this manner is no longer ensured.
In order to overcome the above-mentioned disadvantage it has already been suggested when transporting empty and/or partially filled spools to insert cardboard strips between the outer areas of the upper and lower flanges, the height of such strips corresponding to the flange separation. Cardboard strips of this kind are placed by hand around the spool core and fastened together. It is quite obvious that such a procedure is extremely work-intensive and correspondingly time-consuming and expensive. Furthermore, it has the disadvantage that, when removing the spool from the cassette, the inserted cardboard strip must first be removed before the spool can be put to use. If the spool has then to be stored empty for a lengthy period, it must once more be provided with a cardboard strip. However, in the overwhelming majority of cases this will not happen as the user will not take the trouble himself to place a cardboard strip in the spool in the way the manufacturer did. The result of this is that, in spite of the measures provided by the manufacturer, distortion of the spool will occur after a certain period of use.